The invention relates generally to gasifiers, and more particularly to a gasification quench chamber and scrubber assembly.
In a normal coal gasification process, wherein a particulated carbonaceous fuel such as coal or coke or a carbonaceous gas is burned, the process is carried out at relatively hot temperatures and high pressures in a combustion chamber. When injected fuel is burned or partially burned in the combustion chamber, an effluent is discharged through a port at a lower end of the combustion chamber to a gasification quench chamber, or quench chamber, disposed downstream of the combustion chamber. In other embodiments, there may be a radiant syngas cooler located between the combustion chamber and the quench unit. The quench chamber contains a liquid coolant such as water. The effluent from the combustion chamber is contacted with the liquid coolant in the quench chamber; so as to reduce the temperature of the effluent.
When the fuel is a solid such as coal or coke, the gasifier arrangement permits a solid portion of the effluent, in the form of slag, to be retained in the liquid pool of the quench chamber, and subsequently to be discharged as slag slurry. A gaseous component of the effluent is discharged from the quench chamber for further processing. The gaseous component, however, in passing through the quench chamber, will carry with it a substantial amount of the liquid coolant. A minimal amount of liquid entrained in the exiting gas is not considered objectionable to the overall process. However, excessive liquid carried from the quench chamber and into downstream equipment, is found to pose operational problems. The downstream equipment includes, for example, a scrubber assembly.
In conventional systems, a baffle is placed in the gas exiting path in the quench chamber. Consequently, as liquid-carrying gas contacts the baffle surfaces, a certain amount of the liquid will coalesce on the baffle surfaces. However, the rapidly flowing gas will re-entrain liquid droplets by sweeping droplets from the baffle's lower edge.
There is a need for an improved quench chamber assembly configured to cool an effluent gas from a combustion chamber and also remove entrained liquid content substantially from the effluent gas in a gasifier.